Question

One of the standard solutions had an abnormally low absorbance reading, causing a less positive slope for the calibration curve data plot.

A. The equilibrium concentration of FeSCN²⁺in the unknown solution as determined from the graph will be [ Select ] ["higher than", "the same as", "lower than"] the real one.

This happens because absorbance is [ Select ] ["inversely", "directly"] proportional to concentration with the slope acting as the proportionality constant.

A = slope [ Select ] ["/", "x"] concentration

If the slope appears to be lower, the same absorbance reading will on the graph correspond to [ Select ] ["lower", "higher"] concentration.

B. The calculated K for the equilibrium be [ Select ] ["same as", "higher than", "lower than"] the actual one due to the erred data plot.

K= [ Select ] ["[FeSCN2+]", "[SCN-]", "[Fe2+]"] / [ Select ] ["[Fe2+]", "[SCN-]", "[FeSCN2+]"] [ Select ] ["[Fe2+]", "[SCN-]", "[FeSCN2+]"]

The numerator of the fraction becomes [ Select ] ["smaller", "larger"] , the concentrations in the denominator become [ Select ] ["larger", "smaller"] , and these result in the entire K value [ Select ] ["decreasing", "increasing"]

Answer 1

A PART

S1-lower than

S2-directly

S3- ×(multiplied by)

S4- higher

B PART

S1-lower than

S2-FeSCN2+

S3-Fe2+

S4-SCN-

S5 smaller

S6-larger

S7-decreasing

According to beer Lambert's law absorbance is equal to product of absorption coefficient , concentration and path length .

Here coefficient and path length are treated as constant slope , here absorption changes according to concentration